Differential detection coin discrimination systems and methods for use with consumer-operated kiosks and the like

Abstract

Systems and associated methods for coin discrimination are disclosed herein. In one embodiment, a method for discriminating coins includes obtaining an electromagnetic sensor signal of a coin, generating a contour signal by digitizing the sensor signal, identifying an active interval in the contour signal by eliminating the segments of the contour signal which are close to zero, and detecting the coin approach, pivot and departure points (coin features) from the contour signal in the active interval. The coin features can be compared to known values for different coins to discriminate the coin.

I claim: 
     
       1. A consumer operated coin counting apparatus comprising:
 a coin input region configured to receive a plurality of coins; 
 a coin sensor configured to generate a sensor signal corresponding to properties of a coin; 
 means for generating a contour signal from the sensor signal; 
 means for identifying an active interval in the contour signal; 
 means for detecting a coin feature from the active interval; 
 means for determining a departure point in the coin feature, wherein the means for determining determines the departure point based on a Boolean logic characterized by:
     i   departures   {i :( a   i >0) ( b   i <0) ( f< 0) ( c   i <0) ( n   i ≧0)}; and
 
 
 means for comparing the departure point to a corresponding departure point of a known coin denomination. 
 
     
     
       2. The apparatus of  claim 1  wherein the coin is a first coin, wherein the sensor signal is a first sensor signal, wherein the active interval is a first active interval, and wherein:
 the means for identifying an active interval identifies a second active interval in the contour signal, the second active interval corresponding to a second sensor signal of a second coin; 
 the means for detecting a coin feature detects a second coin feature from the second active interval; and 
 the means for comparing compares the second coin feature to a corresponding feature of a known coin denomination. 
 
     
     
       3. The apparatus of  claim 1  wherein means for generating the contour signal generates a digitized combination of at least two sensor signals. 
     
     
       4. The apparatus of  claim 1 , further comprising means for determining a pivot point, wherein the means for determining a pivot point determines the pivot point based on the Boolean logic characterized by:
     i   pivots   {i :( a   i >0) ( b   i >0) ( f   i ≦0) ( c   i <0)}.
 
 
     
     
       5. The apparatus of  claim 1 , further comprising means for detecting a slope of the contour signal being zero or close to zero. 
     
     
       6. The apparatus of  claim 1 , further comprising means for determining an approach point, wherein the means for determining an approach point determines the approach point based on the Boolean logic characterized by:
     i   arrivals   {i :( a   i >0) ( b   i >0) ( f   i >0) ( c   i <0) ( p   i ≧0)}.
 
 
     
     
       7. The apparatus of  claim 1  wherein the contour signal is a digital signal, the apparatus further comprising means for filtering the contour signal using a digital filter. 
     
     
       8. The apparatus of  claim 7  wherein the digital filter is based on a Hanning filter or a Gaussian filter. 
     
     
       9. The apparatus of  claim 1  wherein the means for identifying an active interval in the contour signal identifies the active interval based on detecting the contour signal being above a threshold signal. 
     
     
       10. The apparatus of  claim 1  wherein the means for generating a contour signal include summing an LD signal and an HD signal. 
     
     
       11. A consumer operated coin counting apparatus comprising:
 a coin input region configured to receive a plurality of coins; 
 a coin sensor configured to generate a sensor signal corresponding to properties of a coin; 
 a digital or analog circuit; and 
 a computer-readable medium, wherein the computer readable medium includes instructions configured to cause the circuit to discriminate a coin by a method comprising:
 generating a contour signal from the sensor signal; 
 identifying an active interval in the contour signal; 
 detecting a coin feature from the active interval; 
 determining an approach point in the coin feature based on a Boolean logic characterized by:
     i   arrivals   {i :( a   i >0) ( b   i >0) ( f   i >0) ( c   i <0) ( p   i ≧0)}; and
 
 
 comparing the approach point to a corresponding approach point of a known coin denomination. 
 
 
     
     
       12. The apparatus of  claim 11  wherein the computer readable medium comprises instructions configured to cause the circuit to discriminate a coin by detecting a slope of the contour signal being zero or close to zero. 
     
     
       13. The apparatus of  claim 12  wherein the computer readable medium comprises instructions configured to cause the circuit to discriminate a coin by detecting a second derivative of the contour signal being zero or close to zero. 
     
     
       14. The apparatus of  claim 11  wherein the coin is a first coin, wherein the sensor signal is a first sensor signal, wherein the active interval is a first active interval, and wherein the computer readable medium comprises instructions configured to cause the circuit to discriminate a coin by:
 identifying a second active interval in the contour signal, the second active interval corresponding to a second sensor signal of a second coin; 
 detecting a second approach point of the second coin based on the Boolean logic characterized by:
     i   arrivals   {i :( a   i >0) ( b   i >0) ( f   i >0) ( c   i <0) ( p   i ≧0)}; and
 
 
 comparing the second approach point to a corresponding approach point of a known coin denomination. 
 
     
     
       15. The apparatus of  claim 11  wherein the computer readable medium comprises instructions configured to cause the circuit to discriminate a coin by determining an acceleration of the coin using at least three coin features. 
     
     
       16. The apparatus of  claim 11  wherein generating the contour signal includes generating a digitized combination of at least two sensor signals. 
     
     
       17. The apparatus of  claim 11  wherein the coin is a first coin, wherein the sensor signal is a first sensor signal, wherein the active interval is a first active interval, and wherein the computer readable medium comprises instructions configured to cause the circuit to discriminate a coin by:
 identifying a second active interval in the contour signal, the second active interval corresponding to a second sensor signal of a second coin; 
 detecting a second pivot point of the second coin based on the Boolean logic characterized by:
     i   pivots   {i :( a   i >0) ( b   i >0) ( f   i ≦0) ( c   i <0)}; and
 
 
 comparing the second pivot point to a corresponding pivot point of a known coin denomination. 
 
     
     
       18. The apparatus of  claim 11  wherein the contour signal is a digital signal, wherein the computer readable medium comprises instructions configured to cause the circuit to discriminate a coin by filtering the contour signal using a digital filter.